Photooxidation of Bilirubin to Biliverdin and Bilirubin Structure

Porphyrin-induced photooxidation of conjugated bilirubin.

Visible light irradiation of 18 microM bilirubin ditaurate (BR-DT) at pH 7.0 for 30 min showed a 10% decrease in absorbance at 445 nm. When the reaction was carried out in the presence of a trace amount of uroporphyrin (UP), the spectrum of BR-DT disappeared without a concomitant formation of biliverdin. Photooxidation products were confirmed to be dipyrrole-containing compounds. Photo-bleachin...

Bilirubin and biliverdin binding to rat Y protein (ligandin).

The binding of bilirubin to poly(L-lysine) produces an optically active complex at pH 10.1. Circular dichroism spectra of these complexes are distinguishable from those generated by binding of bilirubin to the high affinity sites on albumin. Comparison of the circular dichroism spectra of bilirubin bound to the hepatic protein ligandin with those of bilirubin complexed with albumin or polylysin...

Direct Antioxidant Properties of Bilirubin and Biliverdin. Is there a Role for Biliverdin Reductase?

Reactive oxygen species (ROS) and signaling events are involved in the pathogenesis of endothelial dysfunction and represent a major contribution to vascular regulation. Molecular signaling is highly dependent on ROS. But depending on the amount of ROS production it might have toxic or protective effects. Despite a large number of negative outcomes in large clinical trials (e.g., HOPE, HOPE-TOO...

Bilirubin benefits: cellular protection by a biliverdin reductase antioxidant cycle.

Direct bilirubin higher than total bilirubin?

Both total and direct bilirubin measure the formation of azobilirubin, which is detected at 570/660 nm. The total bilirubin reaction contains surfactant and caffeine, which solubilize “indirect” bilirubin and accelerate the reaction (1). Direct bilirubin is a component of total bilirubin and therefore should always be smaller in value. The presence of a monoclonal immunoglobulin (2220mg/dL) fal...